Presently, researches on high-definition video systems such as super Hi-Vision are on-going. Then, in image pick-up using a high-definition video system, a camera is employed that has a high resolution such as 4 k (the number of pixels is horizontal 4096×vertical 2160) and 8 k (the number of pixels is horizontal 8192×vertical 4320).
In cameras of high resolution, for the purpose of achieving high-image quality, assembly errors are requested to be small in each lens group. In general, in lens groups, errors in each lens group are adjusted after the assembly, and adjustment is performed such as to avoid image degradation caused by variations in the inside of each lens group and between lens groups. Nevertheless, in cameras having been assembled, at the time of image pick-up, when a change occurs in the conditions of the optical system such as the position of a movable lens group, decentering could arise that is an assembly error in each lens group. This is because the degree of influence of aberration to decentering of each lens group varies depending on the conditions of the optical system.
Thus, an imaging device is disclosed in Patent Literature 1 in which at the time of image pick-up, on the basis of the conditions of a movable lens group, a decentering lens group is driven and decentered relative to the optical axis of the movable lens group so that image quality is adjusted.